The invention concerns a method and apparatus for defrothing and degassing liquid flowing from the foam duct of a primary flotation cell to a subsequent secondary flotation cell.
An existing difficulty involves the constant feeding of the foam which generally collects in a foam duct in the primary flotation cell arrangement to a pump which feeds the liquid quantity of the foam to the secondary flotation stages. A very large share of air in the foam might call for a generous overdimensioning of the pump, but this is relatively expensive and for operational cases occurring now and then, when said liquid quantity contains only a small share of gas, the control could very easily be thrown off balance because the pump would then feed too much liquid.
As is known, the liquid cleaned in the secondary flotation stage is recycled to the primary flotation stage. This is where the invention sets in solving the problem of enabling a smooth operation of the pump without overdimensioning it through the features described and claimed herein with reference to specific preferred embodiments.